JPH0379540B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an accelerator control device for a vehicle, and more particularly to an accelerator control device that changes the characteristics of the accelerator pedal depression feeling and acceleration feeling in accordance with driving conditions. As is well known, in conventional automobiles, the accelerator pedal and the throttle valve are directly mechanically connected by wires, links, etc., and the opening degree of the throttle valve is unique depending on the amount of depression (displacement, stroke) of the accelerator pedal. It is structured in such a way that it is determined by In this mechanical accelerator system, in order to obtain a good feeling of acceleration in which a slight acceleration of the accelerator pedal is rapidly accelerated, the rate of change of the throttle valve opening relative to the amount of displacement of the accelerator pedal is set to a large value. Fine control of speed becomes difficult. On the other hand, if the rate of change of the throttle valve opening with respect to the displacement of the accelerator pedal is set small with emphasis on fine speed controllability during low-speed running, the acceleration in response to pedal operation will deteriorate. As described above, conventional accelerator systems have not been able to provide characteristics that make driving easy under all driving conditions. This invention was made in view of the above-mentioned conventional problems, and its purpose is to prevent a situation where the control characteristics change during driving and cause an undesired deceleration, and also to prevent the minute speed changes. An object of the present invention is to provide an accelerator pedal control device for a vehicle that can achieve both accurate adjustment and a good feeling of acceleration. In order to achieve the above object, the present invention provides a servo drive means for a throttle valve that opens and closes the throttle valve so that the valve opening corresponds to a given control signal, and a means for detecting the displacement of an accelerator pedal. The pedal stroke detection means is set with a plurality of different characteristics that are approximately proportional to the relationship between the displacement amount of the accelerator pedal and the throttle valve opening, and the throttle valve opening is controlled in accordance with the output of the stroke detection means. control signal generating means for outputting a signal and applying the control signal to the servo driving means; operation start detection means for detecting the timing at which the accelerator pedal starts to be displaced from the zero position; and from the time of detection by the operation start detection means. a timer means for timing a predetermined period of time; and a timer means for measuring the displacement amount or displacement speed of the accelerator pedal while the timer means measures a certain period of time after the accelerator pedal starts to be displaced from the zero position. an operation status determining means for determining whether or not both have exceeded a preset reference value; and when the operation status determining means detects that the reference value has not been exceeded, an accelerator in the control signal generating means; The present invention is characterized by comprising: control characteristic changing means for decreasing the rate of change in the valve opening with respect to the displacement in the pedal displacement/throttle valve opening characteristic, and increasing the rate of change in other cases. In other words, this invention focuses on the fact that when the pedal is operated with the intention of finely adjusting the speed, the displacement amount and displacement speed are kept within a very small range for a certain period of time after the accelerator pedal is depressed. This system detects such pedal operation conditions and automatically reduces the rate of change in throttle valve opening relative to pedal displacement. Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a block diagram showing the hardware configuration of an accelerator system according to the present invention. In this system, from microcomputer 1 to D/A
A control signal (target value of the throttle valve opening) is applied to the servo drive system of the throttle valve via the converter 2. This servo drive system consists of a servo motor 3 that drives the throttle valve to open and close, a valve opening sensor 4 consisting of a potentiometer, etc. that detects the opening of the throttle valve, and a control signal and valve opening given from a microcomputer 1. It consists of a servo drive circuit 5 that drives the servo motor 3 in forward and reverse rotation so that the detection output of the sensor 4 coincides with the detection output. In connection with the accelerator pedal, there is a stroke sensor 6 consisting of a potentiometer or the like that detects the amount of displacement of the accelerator pedal, and a zero position detection switch 7 that is turned on when the accelerator pedal returns to the zero position due to the force of a spring or the like. is provided. A pedal displacement signal APS detected by the stroke sensor 6 is read into the microcomputer 1 via an A/D converter. Further, the pedal displacement amount signal APS is differentiated by a differentiating circuit 9 to obtain a pedal displacement speed signal DAPS, and this displacement speed signal DAPS is obtained.
DAPS is also read into the microcomputer 1 via the A/D converter 8. Further, the timing at which the zero position detection switch 7 changes from ON to OFF, that is, the timing at which the accelerator pedal starts to be depressed from the zero position, is detected by the rise detection circuit 10, and the operation is started by a pulse with a minute width in response to this timing. pulse
AOT is generated, and this signal AOT is also read into the microcomputer 1. The microcomputer 1 performs control and arithmetic processing according to the above-mentioned accelerator pedal displacement signal APS, displacement speed signal DAPS, and operation start pulse AOT, and determines the target value of the throttle valve opening to be applied to the servo drive circuit 5. Output. The throttle valve opening (target value) is set in advance using the accelerator pedal displacement signal APS as an input variable, and is stored in the memory of the microcomputer 1 in the form of a function table. Regarding the functional relationship between accelerator pedal displacement and throttle valve opening, there are two types of characteristics as shown in Figure 3.
CB1 and CB2 are set and stored in the microcomputer 1. In this embodiment, both characteristics CB1 and CB2 have linear characteristics in which the throttle valve opening increases in proportion to the amount of displacement of the accelerator pedal. One of these characteristics, CB1, is selected to have almost the same characteristics as a conventional accelerator system in which the accelerator pedal and throttle valve are directly connected mechanically, and the rate of change in the throttle valve opening with respect to the amount of displacement of the accelerator pedal is relatively large. (Characteristics with good acceleration feeling). On the other hand, the other characteristic CB2 is a characteristic for facilitating fine adjustment of the speed, and the rate of change of the stroke opening degree with respect to the amount of displacement of the accelerator pedal is set to be small. In the present invention, the throttle valve opening degree is controlled in accordance with the characteristic CB1 in normal conditions other than the cases described below. Characteristics suitable for fine speed adjustment
The throttle valve opening is controlled by changing to CB2 in the following cases. Depressing the accelerator pedal is started when the accelerator pedal has returned to the zero position, and the displacement signal APS of the accelerator pedal does not exceed the preset reference value APS1 within a sufficiently small fixed time T ₀ from the operation start timing. Moreover, when the displacement speed signal DAPS of the accelerator pedal does not exceed the preset reference value DAPS1, the control characteristic after the above-mentioned time T ₀ is changed to the characteristic CB2 suitable for fine speed adjustment. The above situation is shown in the time chart of FIG. When the accelerator pedal is depressed from the zero position, the operation start pulse AOT is generated as described above. Microcomputer 1 uses this pulse
In response to AOT, a timer is activated to count the above-mentioned minute constant time _T0 . In addition, while the timer is measuring time T ₀ , the latest displacement signal APS and displacement speed signal DAPS, which are repeatedly sampled, are compared with the reference values APS1 and DAPS1, respectively, and the APS continues during time T ₀ . <APS1 When DAPS<DAPS1, the control characteristics become characteristic after time _T0 .
Changed to CB2. otherwise characteristic CB
Control is performed with the value set to 1. The above reference values APS1 and DAPS1 are the reference values for the displacement amount and displacement speed when many drivers operate the accelerator pedal with the intention of finely adjusting the speed, and are experimentally determined. For example, APS1 is the full stroke of the pedal. DAPS1 is set to a speed at which a full pedal stroke can be achieved in 1 second, and this is done by focusing on the correlation between the driver's intention to finely adjust the speed and the accelerator pedal operation. . An example of a specific processing procedure for realizing the above control performed by the microcomputer 1 is shown in the flowchart of FIG. As shown in Figure 2, the microcomputer 1
is the displacement amount signal of the accelerator pedal at step 140.
APS is read, and in the following step 141, the target value of the throttle valve opening corresponding to the read displacement signal APS is determined, and in the following step 142, the target value is output to the servo drive circuit 5 to set the target throttle valve opening. Make it equal to the value. The characteristic used to calculate the valve opening target value in step 141 is based on either the characteristic CB1 or CB2 stored in the register CB as described later. Using one of the function tables of CB2, the displacement signal APS is calculated using well-known table lookup and interpolation processing techniques.
A target value of the throttle valve opening corresponding to is calculated. In addition to storing the characteristic name CB1 in the above register CB during the initialization process in step 101,
The characteristic name CB1 is stored in steps 130 and 132, which will be explained in sequence below, and the characteristic name CB2 is stored in the register CB in step 131. First, in step 110, when the accelerator pedal operation start pulse AOT is detected, the process proceeds to step 111.
Proceed to and check the flag indicating that pulse AOT has been detected.
It is determined whether the flag FFAOT has already been set to "1", and if the flag FFAOT is not set, the program proceeds to step 112 to set it, and then, in step 113, a timer is set for counting the above-mentioned time _T0 . Start. Note that if it is detected in step 111 that the flag FFAOT has already been set, steps 112 and 113 are skipped. After starting the timer in step 113, the accelerator pedal displacement signal APS is detected in step 120.
and displacement speed signal DAPS, followed by step 1
At 21, is the displacement signal APS greater than or equal to the reference value APS1?
It is checked whether the displacement speed signal DAPS is greater than or equal to the reference value DAPS1, and if either one is greater than or equal to the reference value, the timer is stopped at step 124, and the register CB is set at step 132.
Store CB1 in . Also, in step 121, both data are APS1,
If DAPS1 is not exceeded, step 122
, and checks whether the timer counting time _T0 has timed up. Until this timer times up, the process proceeds to step 130 and stores CB1 in register CB. In addition, in step 110, the operation start pulse is
Even if AOT is not detected, the flag FFAOT is reset to "0" in step 114, and then it is checked in step 115 whether or not the above-mentioned timer is activated, and this timer is measuring time _T0 . If so, proceed to step 120 onwards. After the operation start pulse AOT is generated, the accelerator pedal displacement signal APS and displacement speed signal are
When the time _T0 elapses without both DAPS exceeding the reference values APS1 and DAPS1 and the timer times out, the determination in step 122 is YES. In this case, the timer is stopped in step 123, and the register CB is set in step 131. The characteristic name CB2 suitable for fine speed adjustment is stored in . The process of selecting the above characteristics and the previous step 14
The process from 0 to 141 to 142 is repeatedly executed at high speed, and the accelerator control according to the present invention described above is realized. Here, other embodiments of the present invention will be additionally described. Even without providing the zero position detection switch 7,
The same function can be achieved using the output of the stroke sensor 6. That is, the output of the stroke sensor 6 when the accelerator pedal is at the zero position can be discriminated, for example, by a comparator, and the timing when the accelerator pedal is depressed from the zero position can be extracted. Further, the stroke sensor 6 is not limited to one using a potentiometer, and various position and displacement detectors such as a rotary encoder can be used. Further, the servo drive system for the throttle valve is not limited to an electric mechanism using the servo motor 3, but the same function can be achieved by a servo system using hydraulic or pneumatic pressure. Furthermore, the characteristics of accelerator pedal displacement/throttle valve opening are not limited to the straight line shown in Figure 3, and other curved characteristics may be selected according to the throttle valve characteristics and the characteristics of the servo drive system. . Furthermore, it is also possible to set three or more characteristics of accelerator pedal displacement amount/throttle valve opening degree, and to develop the invention so that the characteristics are selected based on other factors in combination with the present invention. Furthermore, it goes without saying that the calculation function for obtaining the target value of the throttle valve opening based on predetermined characteristics from the displacement amount signal of the accelerator pedal can also be realized by a separate analog calculation circuit using a function generator. In addition, in the previous embodiment, if both the pedal displacement amount and the displacement speed do not exceed the reference values within a certain period of time after the pedal is operated, the characteristic CB for fine speed adjustment is applied.
2 is selected, but the present invention also applies if this standard is set only for either the displacement amount or the displacement speed of the pedal, and if it does not exceed the standard value, characteristic CB2 is selected. Most of the intended effects can be achieved. Furthermore, if the pedal is operated normally without any intention of making fine adjustments, it goes without saying that the engine will operate with a good feeling of acceleration. As explained in detail above, the present invention provides that either or both of the displacement amount and the displacement speed of the accelerator pedal during a predetermined period of time from the time when the accelerator pedal starts changing from the zero position.
If the preset reference value is not exceeded, the valve opening is configured to reduce the amount of displacement of the valve opening relative to the amount of displacement of the accelerator pedal/throttle valve opening characteristic, so the accelerator pedal at the start of operation is It is possible to determine the operation state of the accelerator pedal and change the control characteristics only when the system changes from the zero position. Therefore, it is possible to prevent a situation where the control characteristics change during driving and cause an undesired deceleration, and it is also possible to achieve both fine adjustment of speed and a good feeling of acceleration. have

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an accelerator system according to an embodiment of the present invention, Fig. 2 is a flowchart showing the control contents by the microcomputer 1 in Fig. 1, and Fig. 3 is an accelerator pedal displacement amount/throttle valve. FIG. 4 is a time chart showing an example of the operation of the above system. 1... Microcomputer, 3... Servo motor, 4... Valve opening sensor, 5... Servo drive circuit, 6... Stroke sensor, 7... Zero position detection switch, 9... Differential circuit, 10... Rise detection circuit, AOT...operation start pulse, APS...displacement amount signal, DAPS...displacement speed signal.

Claims (1)

[Scope of Claims] 1. Throttle valve servo drive means for opening and closing the throttle valve so that the valve opening corresponds to a given control signal; Pedal stroke detection means for detecting the amount of displacement of the accelerator pedal; A plurality of different characteristics that are approximately proportional to the relationship between the displacement amount of the accelerator pedal and the opening degree of the throttle valve are set, and a control signal for the throttle valve opening degree corresponding to the output of the stroke detection means is outputted. control signal generating means for supplying a control signal to the servo drive means; operation start detection means for detecting the timing at which the accelerator pedal starts to be displaced from the zero position; and a preset period of time from the time of detection by the operation start detection means. a timer means for timing the accelerator pedal, and one or both of the displacement amount and the displacement speed of the accelerator pedal are set in advance while the timer means measures a certain period of time after the accelerator pedal starts to be displaced from the zero position. an operation status determination means for determining whether the reference value has been exceeded; and when the operation status determination means detects that the reference value has not been exceeded, the accelerator pedal displacement amount/throttle valve in the control signal generation means; An accelerator control device for a vehicle, comprising: a control characteristic changing means that reduces a rate of change in a valve opening with respect to a displacement amount of an opening characteristic, and increases the rate of change in other cases.